Power and cooling (power/cooling) are emerging to be key challenges in electronic system environments that have racks of electronic equipment interconnected in a hierarchical manner. One example of such an electronic system environment is a data center environment that has racks of computer equipment and media storage equipment interconnected hierarchically via network switches, routers, or both. For large data centers, the power consumption can cost several millions of dollars per year in electricity costs. Additionally, increasing power density leads to large costs—both capital and recurring—for power delivery and cooling. The power density also has implications on metrics like compaction, reliability, and uptime. An added motivation to address this problem has come in the form of governmental agencies (e.g., EPA, Intelligent Energy Europe, TopRunner) actively seeking to regulate enterprise power. As a consequence of these trends, there has been a lot of focus within the community on power and cooling. Individual groups designing solutions for the data center all are focusing on power management as a key differentiator for their offerings.
While there has been a lot of progress made on the power/cooling problem, one of the key challenges has been the fact that the proposed solutions only address individual aspects of the problem in isolation. Different solutions regulate power in different ways (e.g., voltage scaling, virtual machine consolidation, power-aware resource scheduling), at different implementation levels (e.g., chip, server, enclosure, datacenter), from different aspects of the solution stack (e.g., hardware, software, firmware), and with varying goals and tradeoffs (e.g., energy, power, heat, energy delay). For example, commercial products already exist that address average power through control of power states, or P states, defined by the Advanced Configuration and Power Interface (ACPI) standard, at the platform level. Additionally, there exist power capping solutions that address peak power at the processor level and at the blade server level. Similar power management can also be implemented at the software level, such as at the operating system (OS) or at the distributed resource scheduler. There also exist solutions that leverage virtual machine (VM) consolidation for power management. Accordingly, the many individual power/cooling solutions occupy a well-populated multidimensional grid across the four axes of mechanisms, implementation level, solution-stack level, and objective function.